Paracrine cell signaling, not differentiation, appears to be how stem cells work in initial phase of organ protection, repair
BETHESDA, Md. (August 16, 2005) Acute renal failure, or ARF, is as serious as it sounds. An estimated 40% of critical care hospital admissions experience ARF. Estimates of their death rate range from 50% to 80%, complicated by the fact that patients with ARF often simultaneously suffer failure of other major organ systems.
The most serious form of ARF is caused by ischemia, or loss of blood supply to the kidneys caused by shock, blood infection or major cardiovascular surgery, particularly in such high- risk patients as those with diabetes, underlying renal disease, and the elderly. In the kidneys, such "insults" lead to destruction of kidney tubular and vascular cells, initiating a significant inflammatory response. Recovery of kidney function that is adequate for patient survival depends primarily on the protection and regeneration of destroyed and injured cells.
Yet virtually no progress has been made toward development of any highly effective ARF therapy for decades. "Basically, catastrophic loss of kidney function has remained treatment-resistant despite dialysis and intensive care. Treating patients with ARF thus presents a major clinical dilemma, particularly when severe ARF occurs with multiple organ failure," Christof Westenfelder from the University of Utah explained. "Our laboratory has therefore been pursuing development of novel therapeutic interventions that are urgently needed to treat this common, devastating and costly human disease," Westenfelder said.
Challenging the accepted theory of stem cell operation
In a new study, Westenfelder's team reported that injecting stem cells similar to the type used in bone marrow transplants is